The plant commonly referred to as “gypsy tree” is the Tree of Heaven (Ailanthus altissima). The term “gypsy tree” is considered culturally insensitive. This article details the species’ characteristics, impacts, and management strategies.
Understanding the Tree of Heaven
The Tree of Heaven (Ailanthus altissima) is a fast-growing deciduous tree native to northeast and central China, and Taiwan. Introduced to the United States in 1784 as an ornamental plant, it quickly spread. Its distinct pinnately compound leaves, 1 to 4 feet long, feature 10 to 41 leaflets. Each leaflet has one or more glandular, notched teeth at its base, distinguishing it from similar native species like sumacs or black walnuts.
The bark is generally smooth and pale gray when young, developing shallow furrows as it matures. In early summer, greenish-yellow flowers appear in large clusters, followed by distinctive winged seeds called samaras. These reddish-brown, twisted seeds persist on female trees through winter, aiding widespread dispersal by wind and water. The tree can reach heights of 50 to 80 feet.
Why Tree of Heaven is a Concern
The Tree of Heaven is a problematic invasive species due to several aggressive characteristics. It exhibits allelopathy, releasing chemicals from its roots, bark, and leaves that inhibit the growth of nearby native plants. This allows it to outcompete and displace diverse native vegetation, significantly reducing biodiversity.
Its rapid growth rate and ability to quickly colonize disturbed areas make it a formidable invader. The tree reproduces aggressively through prolific seed production and extensive root suckering, forming vast underground networks. These vigorous root systems can damage infrastructure, including sidewalks, building foundations, and underground pipes.
Beyond its direct ecological and structural impacts, the Tree of Heaven serves as a primary host for the invasive Spotted Lanternfly (Lycorma delicatula). This insect pest strongly prefers the Tree of Heaven, utilizing it for its life cycle and laying egg masses on its bark. The tree’s presence facilitates the spread of this destructive insect, which can severely damage agricultural crops, including grapes and stone fruits, as well as other hardwood trees. Additionally, pollen from male Tree of Heaven trees can cause allergic reactions in some individuals, including rhinoconjunctivitis and asthma.
Effective Management and Removal Strategies
Controlling the Tree of Heaven requires persistent effort due to its vigorous re-sprouting capabilities. Hand-pulling small seedlings can be effective if the entire root system is removed. However, cutting alone is generally ineffective for mature trees, as it stimulates aggressive re-sprouting from the stump and roots, often leading to a denser stand.
Chemical treatments are often the most effective method for established trees, particularly systemic herbicides that translocate to the roots. Basal bark applications, where a herbicide mixed with oil is sprayed around the lower 12 to 18 inches of the trunk, work well on smaller trees (up to 6-8 inches in diameter). For larger trees, the “hack-and-squirt” or stem injection method involves making downward angled cuts into the bark and immediately applying concentrated herbicide. This method targets the tree’s vascular system, ensuring the herbicide reaches the roots.
Another effective approach is the cut-stump method, where the tree is cut close to the ground, and a herbicide solution is immediately applied to the freshly cut surface. This technique is best performed when sap flows downwards to ensure the herbicide moves to the roots. Regardless of the chemical method chosen, follow-up monitoring and re-treatment of any re-sprouts or new seedlings are crucial for long-term control. Always consult and follow herbicide label instructions for proper application, safety, and personal protective equipment.
Native Alternatives for Your Landscape
Replacing the invasive Tree of Heaven with native species can enhance local biodiversity and support wildlife. Consider planting native maples (Acer species), such as Red Maple (Acer rubrum) or Sugar Maple (Acer saccharum), which offer vibrant fall color. Native oaks (Quercus species), like White Oak (Quercus alba) or Northern Red Oak (Quercus rubra), provide significant ecological benefits and long-term landscape value. Other suitable alternatives include native sumacs (Rhus species), which resemble the Tree of Heaven’s leaf structure, or species like Black Gum (Nyssa sylvatica) for their attractive foliage and hardiness.